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JUNE 1, 1873. 




BROOKLYN: 

EAGLE PBINT, 34 AND 36 PULTON STEEET. 











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REPORT 


•OF' TIIE 


EXECUTIVE COMMITTEE. 


To the Board of Directors of the New York Bridge 

Company : 

Gentlemen :— 

The Executive Committee respectfully present their 
annual report. 

Under authority conferred upon them by resolution 
of the Board, they have continued with the construction 
of the bridge, for the past year, as rapidly as circunl- 
stances permitted. The Tower on the Brooklyn side 
has been carried up to an elevation of 100 feet 
above high water, and is progressing steadily upward. 
The foundation of the Tower on the New York side of 
the river has been sunk to its final depth of about 80 
feet, and is so far advanced that in the course of a 
month more it will, if no accident intervene to prevent 
it, be filled in and finished to above high-water mark. 

For the history and progress of the work during the 
year they refer with great satisfaction to the report of 
the Chief Engineer, W. A. Roebling, Esq., now 
presented. 

For the financial condition of the Company they 
refer to the statement hereto appended, showing the 
receipts and expenditures of the Company from the 





4 


commencement of the work to the first day of May, 
1872. 

The report of the Superintendent shows the opera¬ 
tions on the work, and is also now presented. 

S. L. HUSTED, 

J. S. T. STEAYAHA^, 

HEYEY W. SLOCUM, 

HEYEY C. MUEPHY, ex off., 

Committee. 


Brooklyn, June 3, 1872. 


Statement of the Receipts and Expenditures of the New 
York Bridge Company to and including April 30, 1872. 

RECEIPTS. 


Capital stock paid in. $2,762,400 00 

Rent. 4,560 00 

Material sold. 2,754 85 

Interest on deposits. 30,321 70 

Wharfage at Pier 29. 3,587 71 

On sale of New York city bonds. 120,000 00 


$2,923,624 26 


EXPENDITURES. 

Engineering. $126,009 26 

Rent. 20,808 33 

Office expenses. 23,00i 22 

Timber and lumber. 332,564 10 

Construction. 722,891 70 

Contingent expenses. 10,159 79 

Tools. 13,634 18 

Labor. 369,062 76 

Machinery. 108,154 19 

Freight, cartage, and towage. 9,617 06 

Printing and advertising.. 1,092 51 

Land, land damages and buildings. 332,673 65 

Limestone. 171,277 09 

Insurance. 1,441 • 87 

Scows. 27,940 57 

Interest. 1,998 89 

Horses, wagons, and harness. 1,762 18 

Granite. 371,957 44 

Taxes. 3,772 76 

Office furniture. 5,337 23 

Bonds of the city of New York. 248,000 00 

Bodwell, Webster & Co., freight on account. 2,232 71 


Total...$2,905,389 49 


Total receipts..$2,923,624 26 

Total expenditures.;. 2,905,389 49 


Balance of cash account.. $18,234 77 












































6 


Cash in Brooklyn Trust Co. $1,672 05 

“ “ Atlantic National Bank. 14,028 56 

16 “ Long Island Bank. 1,610 14 

Petty cash on hand. 924 02 


$18,234 77 


JOHN H. PRENTICE, 

Treasurer. 

Brooklyn, Mayl, 1872. 










THIRD ANNUAL REPORT 


OP THE 

CHIEF ENGINEER N. Y. BRIDGE COMPANY. 

JUNE 1, 1878. 


To the Hon, Henry 0. Murphy, President N. Y. 

Bridge Co. : 

Sir :— 

I have the honor to present the following report of 
operations on the East River Bridge during the past 
year. 

On the Brooklyn Tower the masonry has been car¬ 
ried up within 20 feet .of the roadway, and is pro¬ 
gressing steadily. 

On the Yew York side the whole winter season has 
been occupied in sinking the Caisson for the Yew 
York Tower. 

In the month of May a satisfactory foundation was 
reached at a depth of 78 feet below mean high water, 
just one year since the launch of that Caisson. The 
operation of filling the air chamber is now rapidly pro¬ 
gressing. When this is completed, work will be resumed 
on the masonry, which is at present 4 feet above 
high water. 

To such of the general public as might imagine 
that no work had been done on the Yew York Tower, 



8 


because they see no evidence of it above the water, I 
would simply remark that the amount of masonry and 
concrete laid on that foundation during the past 
winter, under water, is equal in quantity to the entire 
masonry of the Brooklyn Tower visible to-day above 
the water line. 

I also take this opportunity of congratulating the 
Board of Directors on the success which has attended 
the last of the two great Tower foundations of the 
East Biver Bridge. At the commencement of the 
enterprise they constituted the principal engineering 
problefn to be overcome, and not until they were 
accomplished facts could it be said that the project of 
the bridge was placed upon a firm, immovable footing. 

The subsequent building of the Towers and of the 
superstructure is all work that has been done before on 
a smaller scale, but upon the Tower foundations rests 
the stability of the entire work. The whole enterprise 
depended upon their success. Considerable risk and 
some degree of uncertainty was necessarily involved in 
their construction. 

These have all been overcome, and when we see the 
New York Tower rising above the waters of the East 
Eiver this summer, the people of .the two cities will 
acquire increased confidence in the early realization of 
a work so essential to their mutual prosperity. 

THE NEW YORK FOUNDATION. 

% 

The last annual report contained a very full and 
detailed description of the sinking of the Brooklyn Cais¬ 
son. The account of this work, as well as of other 
large works executed elsewhere, has made the opera¬ 
tion of Caisson sinking familiar to all. 

It is therefore proposed to touch only upon such 


9 


points of the New York foundation wherein it differs 
materially from the Brooklyn foundation. 

BORINGS. 

The borings made heretofore on the site of the New 
York foundation had been .confined only to the small 
area covered by the old pier 29. It was very desir¬ 
able to continue them over the remaining portion of the 
foundation as soon as the adjacent ferry slips were 
vacated. 

This occurred at so late a day, that only four more 
bore-holes could be put down before the Caisson was 
ready for sinking. 

The knowledge derived from nine small bore-holes 
was therefore the sole information we possessed of an 
entire area of 17,500 square feet. These holes being 
moreover confined to the outer edges, left the central 
portions a terra incognita. 

The results showed an extreme difference in the lev¬ 
els of the bed rock of 12 feet, the hole of the least 
depth touching rock at 80 feet below high water, and 
the deepest at 92 feet. 

The strata consisted in the main of a black mud 
deposit of 12 feet, followed by a layer of coarse sand of 
6 feet which overlaid a gravel bed of the same thick¬ 
ness. Beneath the gravel appeared a very heavy 
deposit of quicksand, varying from 15 to 20 feet, accord¬ 
ing to locality, and abounding with boulders in its lower 
portion. 

This quicksand extended usually to within a few feet 
of the rock, and in some instances to the rock itself. 
But the immediate rock surface was covered with a com¬ 
pact layer of material through which it was impossible 
to drive a 6-inch pipe without shattering it. To drive the 


10 


pipe one inch only, required thirty blows of a 500-pound 
hammer falling from a height of 20 feet. But even in 
such material the quicksand would run into the pipe 
from below and till it up for several feet. 

When the sinking of the Caisson commenced, this 
question still remained undecided, whether to go to 
rock or remain above it. 

In case of the former alternative, we had the means 
at hand for blasting the entire rock to a level surface if 
necessary, and of removing the blasted material, at an 
additional expense, it is true, of several hundred thou¬ 
sand dollars and six months more time. 

Or, in case the material on the rock proved water¬ 
tight, it would he feasible to sink a requisite number of 
smaller foundations to the bed rock, sufficient to hold 
the immediate weight above, and then, by a series of 
smaller coffer-dams or cylinders, remove the remainder 
of the material and thus get a uniform mass of mate¬ 
rial between the rock and the roof of the air chamber. 

The only course therefore left open under the cir¬ 
cumstances was to proceed with' the work, and, when 
the Caisson had arrived within'a short distance of the 
rock, make a sufficient number of soundings, and then 
determine upon a course of action when we were face 
to face with the material. 

The character of these bore-holes had also made it 
apparent that any single plan of operations would not 
be adequate for removing all the material we would 
encounter. The immediate river bed consisted of logs 
and loose dock stones, followed by a sticky, black clay. 

These materials could evidently be best removed by 
dredges working in water shafts. 

The river sand and firm gravel beneath would be 
easier removed through pipes, either by pumps or the 
air pressure direct. 


11 


The coarser gravel, however, would go to the water 
shafts; whereas the fine quicksand would again.be 
blown out through pipes, until the preponderance of 
boulders and small rounded stones, compelled a re¬ 
course to the water shafts again, provided any dredge 
whatever had the capacity to remove stones imbedded 
in quicksand. 

For a direct removal of material through locks, no 
special means were deemed necessary beyond the am¬ 
ple facilities afforded by four capacious air locks already 
at hand. 

PREPARATIONS FOR SINKING THE CAISSON. 

Owing to the vexatious delays in obtaining posses¬ 
sion of the ferry slips adjoining Pier 29, nothing of any 
importance could be done in the matter of locating 
machinery or workshops until August, when the ferry¬ 
boats finally ceased running into their old slips, and the 
new boundary line was established between the proper¬ 
ty of the Ferry Company and the Bridge Company. 

The month of August and part of September were 
employed in building a pile dock from the bulkhead 
line out to the Caisson, averaging 450 feet in length 
and 180 feet in width. 

At its outer end was formed a square inclosure, 
open on the river side, for the purpose of receiving the 
Caisson when it was ready to be towed up from the 
Atlantic Basin. 

The amount of space on the pier line was so scant, 
that a narrow platform of 10 feet width constituted all 
the available room between the sides of the Caisson 
and the fender rack of the ferry on the one side, and 
the crowded shipping of the adjoining slip on the other, 
showing that economy of space during erection is not 
the least of the merits of caisson foundations. 


12 


INCLOSUBE OE CAISSON. 

For the purpose of obtaining still water, the Caisson 
was surrounded by a wall of sheet piling, composed of 
white pine plank 50 feet long and 6 inches thick. This 
served to break the force of the tidal current, which 
often runs at the rate of four miles per hour, and would 
produce a pressure of 90 tons against the structure at 
a time when it is most important to have it stationary 
in its true position—-just before touching bottom. 

This entire work of pile-driving and dock-building 
was superintended in the most efficient manner by Mr. 
George MeNulty. 

Within the inclosure thus formed the bottom was 
dredged to a uniform level of 37 feet below high water, 
by means of the clam-shell dredge of Messrs. Morris 
& Cummings, who did this portion of the work under 
contract. 

They removed in all 7,000 yards of material, of which 
1,500 yards consisted of dock stone and logs. 


MACHINEBY AND WOBKSHOPS. 

On the pile platform thus prepared were erected two 
engine houses for the dredge machinery, which was 
transferred from the Brooklyn side, and had been 
enlarged to correspond to the increased depth to which 
this Caisson would go. 

Two double hoisting engines were set up, both for 
unloading stone and setting stone on the Caisson. 

Four additional double engines were provided for 
unloading sand, gravel, coal, cement, and lumber, for 
hauling dredge cars hack and forth, pumping gas and 
mixing concrete. 


13 


The principal building, however, was the 

COMPEESSOE HOUSE. 

for supplying air to the Caisson. 

The air-pumping machinery comprised thirteen of 
the Burleigh rock drill air compressors, ranged in a 
single row, each discharging its air into one common 
10-inch main overhead, and provided with suitable 
valves to shut it off from the main system. 

Every compressor has its own steam boiler of the 
vertical tubular type, so connected as either to work 
independently or as an entire set. Pumps for cooling 
the air were also in duplicate. 

Six of these compressors were brought from the 
Brooklyn Caisson, the remaining seven being purchased 
anew. 

From the compressor house the air was carried by a 
10-inch cast-iron pipe through an intermediate air 
reservoir, for a distance of 150 feet under the dock, to 
the Caisson, whence two branches of 6-inch rubber 
hose continued it by means of the supply shafts to the 
air chamber below. 

The idea governing the general arrangement of the 
air pumps was the necessity of an uninterrupted sup¬ 
ply of air, day and night, for at least a year, under a 
constantly increasing duty. 

This could only be done by a number of smaller ma¬ 
chines, so that if one were out of repair the remainder 
would have sufficient capacity for the work. 

Besides the buildings for machinery and offices, a 
number of sheds were erected for the accommodation 
of blacksmiths, carpenters, machinists, for cement and 
for general stores; also wash-rooms, clothes-houses, 
hospital, and resting-rooms for the Caisson men. 

Three unloading derricks, a double railroad track, 


14 


and two overhanging platforms comprised the prepara¬ 
tions on the dock for supplying the Caisson derricks 
with stone. 

TOWING THE CAISSON INTO POSITION. 

All preparations for receiving the Caisson being com¬ 
pleted by September 11, it was on that day towed 
from the Atlantic basin to its final resting place. While 
at the basin, seven additional courses of timber and con¬ 
crete had been built upon it under contract with Mr. 
D. Burtis, Jr. All the oftter seams were caulked and 
protected by felt, tin, and creosoted sheathing. The 
various pipes, shafts, and locks were also carried up the 
necessary height. 

This work was very carefully attended to under 
direction of Col. Paine. 

Four air pumps and boilers placed on the deck served 
to inflate the structure during the voyage. Its draft, of 
water when empty was 23 feet, reduced by inflation 
to 17. 

Total weight, 7,000 tons. 

Under the skillful guidance of Capt. Murphy, and 
the assistance of six tugs, the trip was safely per¬ 
formed in two hours and a half. A few days’ work 
then sufficed to complete the pile inclosure and confine 
the Hew York Caisson in its permanent position. 

« 

ADDITIONAL TIMBER COURSES. 

By the 1st of November the last of the timber 
courses was laid under the Burtis contract. 

The great timber foundation was now complete ! It 
contains 22 feet of solid timber above the roof of the 
air chamber, seven courses more than the Brooklyn 
Caisson, and since the strength of such structures varies 


15 


as the square of the depth, we may consider it to he 
nearly twice as strong as its Brooklyn brother. 

The result has proved this. At a depth of 78 feet, 
and a load on its hack of 53,000 tons, not the slight¬ 
est sign of weakness or crippling has been discovered! 
No deflection has been observed in the roof, even when 
the main flames and edges below were entirely dug out 
and not resting on the ground. The principal object 
of these frames is at most a precautionary one, besides 
serving to fill up the air chamber to the extent of their 
bulk. 


OUTEB COFFEE-DAM. 

An outer coffer-dam has been carried up outside of 
the masonry. It is composed of upright posts 12 x 12 
placed 4 feet apart, with an outer planking of white 
pine 6 inches thick. Shores extend from each post 
to the masonry, arranged in tiers for every three courses 
of stone. 

The coffer-dam commences' 7 feet below the upper 
course of timber, where it is attached to the Cais¬ 
son by a heavy creosoted sill and screw-bolts. The 
space between it and the timber is filled with concrete, 
14 feet in height, beneath which the outer covering of 
tin extends for ,5 feet. The upper layer of timber is 
covered with 3i feet of concrete, amounting in all to 
3,500 yards. 

Under certain circumstances it would have been pos¬ 
sible to omit this outer coffer-dam and save the con¬ 
siderable . expense attending it. On the Brooklyn 
foundation no outer coffer-dam was used, the depth of 
water being too shallow. 

In any case it was necessary to carry up the dam for 
a height of 25 feet. When the last course of timber 
was laid, the Caisson was still floating 2 feet from 


16 


the bottom at low water, and 10 feet at extreme 
high water. To keep it on the bottom at extreme 
high water required four courses of masonry, and when 
inflated with air, three additional courses were re¬ 
quired. 

Owing to the rise and fall of the tide and the great 
top weight of the structure, the requisite buoyancy 
and stability could only be attained by the displacement 
of a coffer-dam, especially as the usual appliances of 
suspended screws, for keeping the structure level when 
afloat, were obviously inapplicable. 

It had also been intended to surround the Tower by 
a permanent dock of stone and concrete, the founda¬ 
tions of which could now be laid within this coffer-dam 
at a moderate expense. This intention was, however, 
abandoned owing to the necessity of strictly confining 
the expenditure of money to the bridge proper. At 
present the coffer-dam has been designedly filled up 
with sand, and forms part of the timber dock extending 
to the Tower masonry. 

It will last for fifteen years without renewal. 

The coffer-dam also formed a protection to all the 
Caisson pipes, and made it possible to repair them 
when out of order. 

These pipes consisted of four supply shafts of 2 
feet diameter and sixty pipes of 4 inches and 3i 
inches. None of them were built in the masonry, but 
came up between the wall and the coffer-dam. 

On one occasion, through the accident of a large 
stone falling, a supply shaft was broken off at the 
timber line, and would have been lost but for the coffer¬ 
dam. But the chief benefit derived from it was the 
fact that the masonry was laid below the water level 
during most of the winter. The work of sinking 
the Caisson could therefore proceed uninterruptedly, no 


17 


matter if the masonry stopped on account of the cold 
weather. 


INNER COFFER-DAMS. 

Two smaller inner coffer-dams served as a water¬ 
tight lining to the main well holes of the masonry. 
Within them were carried up the sections of water 
shaft, as well as the curbing of the air-lock shafts. 

As far as the timber extends, this curbing consists of 
a boiler-plate shell, stiffened by flanges and secured to 
the timber by wood-screw bolts. The wooden curbing of 
6-inch plank was notched, dowelled, and caulked, and 
further protected on the outside by a ring of concrete 
between it and the inner coffer-dam. The leakage has 
been practically none. 

DERRICKS AND MASONRY. 

The stone were laid by three boom derricks, similar 
to those employed on the Brooklyn foundation. They 
were guyed solely from the Caisson itself, so that the 
settling of the latter did not disturb the guys. Every 
20 feet the derricks had to be raised, an operation 
requiring a few days. 

Twenty-five courses of stone have been laid on top of 
the timber, making a height of 50 feet, and amounting 
in all to 11,700 cubic yards of masonry. 

The stone are all bedded down to a uniform rise in 
one course, with joints dressed down to moderate pro¬ 
jections, the rises varying from 20 to 30 inches. Both 
granite and limestone were used indiscriminately, the 
former coming principally from Maine, and the latter 
from Kingston, Lake Champlain, and Ganajoharie. 

Owing to the early commencement of winter, much 
of the stone in transit for the Kew York Tower was 
frozen in, and, in order to keep on setting, it be- 
2 


18 


came necessary to use all the backing intended for the 
Brooklyn Tower. This has been supplied since, and at 
no time has there been any stoppage for want of 
stone. 

During the severest weather, work was suspended for 
several days at a time, the coffer-dam preventing the 
river from covering the wall. 

WORK IN THE AIR CHAMBER. 

By the end of November sufficient weight had been 
placed on the Caisson to prevent its rising for a short 
time at low tide when inflated. 

A gang of laborers commenced work for several 
hours every day, taking up the floor of the air cham¬ 
ber and removing the principal obstructions in the 
shape of dock logs and stones under the edges and 
frames. 

In proportion to the weight above, the length of 
time spent below was increased, until two regular gangs 
were at work, four hours on and four hours off, the Cais¬ 
son being now permanently grounded. 

Each gang consisted of about seventy laborers and 
seven foremen. In a short time an extra night gang 
was also established. Two weeks were consumed in 
removing and taking out the floor. 

This floor proved a valuable adjunct in giving the 
Caisson a level bed on which to rest, and in preventing 
it from tipping up on either end before sufficient weight 
had been placed on it. 

The character of the work at this particular time was 
more disagreeable than at any subsequent period. 
This location had for many years been the site of 
the principal dumping-ground for city garbage. The 
mud abounded in decaying animal and vegetable re¬ 
mains. Although the odor of these was checked while 


19 


imbedded in the salt water mud, it came forth in its 
original strength when brought in contact with the 
Caisson air. More men were overcome by foul air 
than by compressed air. 

By keeping the material constantly covered with 
water, so as to cover the odor, it was gradually dis¬ 
posed of through the water shafts. 

This black dock mud is really a clay, and is the silt 
brought down by the North Biver, merely lacking time 
and pressure to make it as hard and tenacious as ordi¬ 
nary clays. It derives its black color from sewer dis¬ 
charges, but is by no means their product. 

The coarse river sand and beach gravel beneath the 
mud soon created a change for the better below. The 
water was easily expelled by the air, leaving it dry 
under foot. 

By this time also the gas-lights were in complete 
operation in all the chambers, giving ample light in 
every part. Two coats of whitewash over the roof and 
walls aided in reflecting it and making the air chamber 
an agreeable spot compared with what it was at the 
beginning. 

The performance of the 

DREDGES 

in the mud and coarse sand and gravel was very satis¬ 
factory. They constantly maintained a hole about 6 
feet in depth under the water-shafts, and removed from 
300 to 400 yards per day. 

Water for the shafts was supplied by two sets 
of 4-inch pipes, one of fresh water from the city 
mains, the other connecting with a force pump on 
the dock, which threw in a constant supply of salt 
water under great pressure, and proved of considerable 
use subsequently in loosening boulders under the water 


20 


shafts. Owing to the fact that the shafts were 50 
feet from the nearest edge of the Caisson, a supply of 
water from the river without could at no time he relied 
upon. 


THROWING OUT SAND THROUGH PIPES. 

About fifty pipes were located in the roof of the Cais¬ 
son, passing up through the timber, and discharging- 
above beyond the coffer-dam. In size they varied from 
3i to 4 inches. 

The precise mode in which they were to be utilized 
in throwing out sand had been to a certain degree left 
undetermined. Two modes were applicable, either to 
throw out the sand by direct force of air, or else have 
recourse to sand pumps. 

Very satisfactory experiments had been made the 
year before in the Brooklyn Caisson, in throwing out 
sand through pipes by air pressure. 

The same mode had been used ten years previously 
by Gen. S. Smith and Mr. C. C. Martin in blowing sand 
out of cylinders, and more recently at Omaha under 
similar conditions. 

The apparatus is very simple, consisting merely of a 
piece of pipe and a through way cock extending into 
the air chamber. 

Moreover, the objection of a very small air space to 
draw upon, as is the case in pneumatic cylinders, would 
not apply in a large caisson, which constitutes a large 
reservoir in itself, and would retard any rapid fall of 
pressure. 

Another strong reason in favor of the air process was 
this: an air chamber with an iron skin can be made 
practically air tight, but a certain quantity of air must 
be thrown in per minute to keep the air fresh and fit 
to live in. This air would usually escape under the 


21 


edges and do no work. Now, why not allow it to 
escape through pipes and at the same time carry out 
sand with it, and not he wasted ? There was ample 
air-pump power, thirteen compressors having been pro¬ 
vided, of which number four only were required to 
supply the leakage, but six to supply sufficient fresh 
air. 

Any other mode, however, of sending out the material 
would require extensive provision of machinery in 
the shape of pumps, boilers, and pipes, entailing an 
additional cost of at least $40,000, and difficult of 
application for want of the required space around the 
foundation. 

In view of these considerations, it was first deter¬ 
mined to give the air system a thorough trial. 

The result has been eminently satisfactory. At a 
depth of 60 feet sand was discharged through a 3i inch 
pipe continuously for half an hour at the rate of one 
yard in two minutes. This represents the labor of 
fourteen men standing in a circle around the pipe and 
shoveling as fast as their strength would permit. At 
this depth the supply of air was sufficient to supply 
three pipes at a time. This may appear a small num¬ 
ber compared with* the whole number of pipes, but yet 
was enough to keep at least sixty men busy. 

The labor in itself is very fatiguing, making frequent 
resting spells necessary; more hands are required to 
throw the sand to the pipes than to feed them, and a 
large proportion of labor is expended in digging out 
under the frames and edges. 

The most economical mode of working these pipes 
was made the subject of many trials by Ool. Paine and 
Mr. Oollingwood, the engineers in charge in the Caisson. 
Trials were first made with flexible pieces of hose pro¬ 
vided with strainers at the end. These became choked 


22 


too easily both in the holes of the strainer and in the 
hose. The strainer was then removed and a shorter 
piece of vertical hose used, in connection with a piece 
of iron pipe. This in turn was discarded for a station¬ 
ary iron pipe, extending within a foot of the ground 
and provided with a stop cock below the roof. 

Around the lower end of this pipe the sand and earth 
were heaped up in shape of a cone, while another 
workman attended to the opening or shutting ol the 
air cock. 

As the pressure increased, the lower orifices of the 
pipes were reduced to 3 inches and finally 2 inches, the 
same quantity of material being reduced with a smaller 
loss of air. 

The material of course passes out with tremendous 
velocity, stones and gravel being often projected at 
least 400 feet high. When the feeding below was too 
slow or irregular, the sand would be thrown very high, 
but by practice the discharge soon became more uniform. 

In order to deflect the sand at the top of the pipe at 
right angles, both wrought and cast iron elhows were 
used at first. The sand blast would generally • cut 
through these in an hour or two, sometimes in a few 
minutes, the thickness of iron being li inches. That 
portion of the elbow struck by the sand was then made 
open and provided with a thick cap of chilled Franklin- 
ite iron, capable of being reversed when worn on one 
spot. These would at most last two days. Finally all 
elbows were taken off, heavy granite blocks placed 
over the mouth of the pipes, and the material dis¬ 
charged against them into the coffer-dam. 

Several minor casualties occurred from the discharge 
of stones, such as a boatman on the river having his 
finger shot off and a laborer being shot through the 
arm by a large fragment. 


23 


Some inconvenience was experienced from the wear¬ 
ing out of the ends of the pipes below in the air cham¬ 
ber. The cocks also wore out rapidly, owing to care¬ 
less attendance in not opening them all the way. The 
pipes in the timber did not wear. When a 4-inch pipe 
had become cut, a 3|-inch pipe, was driven inside of it, 
then a 3-inch, and at last a 2-inch. But they lasted so 
well on an average, that one-third of the pipes were 
never used. 


QUICKSAND. 

When the quicksand was fairly entered upon, it was 
found that the dredge buckets no longer operated to 
any advantage. This sand, in combination with small 
stones and boulders, will compact to a mass as hard as 
rock, which can not be penetrated by the teeth of a 
bucket, and even the point of a crowbar can scarcely 
be driven into it. 

Some slight relief was experienced by the use of a 
hose under the shaft to stir up the material, but even 
then the sand was so fine as to escape through the 
slightest crevice in the buckets. 

The sand pipes became henceforth the sole reliance, 
and answered admirably, until the coarse gravel and 
stones became so plentiful as to choke the ends of 
the pipes, making it necessary to stop for a moment to 
remove the stone. 

The. work of the last 10 feet, from 68 to 78, was on 
this account very tedious and slow. Previous to 
this the progress had at times averaged a foot per 
day of 16 hours, implying the removal of 650 yards 
per day, but toward the end this rate decreased to 1 or 
2 feet per week. 


24 


CUTTING OFF THE WATER SHAFTS. 

At a depth of 68 feet a number of boulders were en¬ 
countered under one water shaft, too large to be moved 
either by the dredge or by outside appliances. It 
therefore became necessary to cap the shaft and blow 
out the water, similar to the operation so frequently 
performed in Brooklyn. On top of the cast-iron cap 
was placed one of the old air locks, so as to afford 
access into the shaft hereafter. 

After the water was blown out and boulders removed, 
the shaft was cut off near the roof of the air chamber. 
The same process was repeated with the other shaft. 
During this time the Caisson was kept from sinking by 
banking up the frames and edges with earth. 

The air pressure against the caps of the shafts is 133 
tons. The individual sections had been tested to twice 
this pressure before, but by way of precaution an addi¬ 
tional dead weight of 50 tons was placed on them. 

Where water shafts are used, it is absolutely necessary 
to make provisions for capping them. 

SOUNDINGS FOR ROCK. 

At a depth of 70 feet, soundings were begun in the air 
chamber for the location of bed rock, by means of a 
pointed rod, ten feet long, driven in by sledges. 

A trial was made to sound by means of a pipe and 
water jet, but was abandoned on account of the numer¬ 
ous stones. These probings were carried on daily for a 
month, until a clear idea of the form and depth of bed 
rock was attained. 

The surface was evidently very irregular, composed of 
alternate projections and depressions, the extreme dif¬ 
ference in elevations encountered being 16 feet, and 
occurring chiefly along the water edge. Throughout 


25 




the central portion, however, and covering at least two- 
thirds of the entire area, the irregularities were much 
less, amounting to only 3 or 4 feet in a length of 160, 
and width of about 75 feet. 

The Caisson would apparently settle on a broken 
ridge of rock, running diagonally from one corner to the 
other, and having a moderate dip of perhaps 5 feet in 
the hundred toward the land; hut falling off very 
suddenly toward the east corner in number one cham¬ 
ber. 

With these facts before us, it was evident that it 
would be a matter of immense expense and great loss 
of time to blast down the rock to a comparatively level 
surface; but unless this were done, it would appear 
equally dangerous to allow the Caisson to rest on the 
rock at one end and not on the other. 

Fortunately one circumstance put a more favorable 
appearance upon the case, and that was that the top of 
the rock was found to be covered for a depth of 2 to 
4 feet by a layer of very compact material, so hard 
that it was next to impossible to drive in an iron rod 
without battering it to pieces. 

Moreover, where the rock lay the lowest, this layer of 
hard material had its greatest thickness. 

It was good enough to found upon, or at any rate 
nearly as good as any concrete that could be put in 
place of it. In extent it covered fully three-fourths of 
the Caisson, leaving a narrow strip of quicksand along 
the land edge, and a triangular portion over part of 
number one and six chamber. 

Since the lower line of the quicksand sloped at the 
rate of 6 feet in the hundred, it became necessary to 
penetrate about 5 feet into the hard ground on the 
water edge, before the bottom of the quicksand was 
reached on the land side. The number of boulders 


26 


found in it was very large, much greater than were 
found in the same space on the Brooklyn side. 

It was determined to rest the Caisson on this ma¬ 
terial at a depth of 78 feet. The projecting peaks of 
bed rock which already made their appearance at 75 
feet, were blasted down for some distance under the 
shoe, and covered with a foot of compressible earth. 

In number six chamber a trench was sunk through 
the remaining quicksand under the edge, and filled 
with concrete to confine the portion remaining within; 
a task of no small difficulty, owing to the influx of water 
and sand. 

Any other small irregularities will he fully equalized 
by the great timber platform above. 

BED BOOK. 

The first spurs of bed rock were encountered at a 
depth of 75 feet, under the shoe on the water-side. It 
would seem that the Caisson had been scraping along 
a vertical wall of rock for the previous five feet at that 
spot. 

The rock is the ordinary gneiss found on Manhattan 
Island, with a dip almost vertical. Eo part of its 
surface shows the rounding action of water or ice. On 
the contrary, the outcrop is in the form of sharp thin 
ridges, with steep vertical sides occurring in parallel 
ranges. 

On such a bottom no sliding can ever take place, no 
matter what the average slope might he. At 78 feet 
the outcrop was struck in a number of places and 
blasted down a short distance below the edge. A 
slight covering of soil gave the necessary amount of 
compressible material above these rocky points. Near¬ 
ly all of them occurred under the edge on the water-side, 
a favorable circumstance, since the resultant of pressure 


27 


is in that direction. No fresh water was found on the 
rock, but salt water entered upon a reduction of 
air pressure. 

FILLESTGr OF THE Alii CHAMBEK. 

The concrete for filling the chamber is all mixed 
above and let down through the supply shafts ready for 
distribution below. 

No brick pillars were used as under the Brooklyn 
Caisson, the bearings of the frames being so wide as to 
be equal to all contingencies when once uniformly 
packed under with concrete. The stones, earth, and 
sand left in the Caisson during the sinking were suffi¬ 
cient to fill one-third of the space, and since the con¬ 
crete is going in at the rate of 80 to 100 yards per day, 
it is probable that the chamber will he filled in the 
early part of July. Final exit will he had by the water 
shafts. 

EFFECTS OF THE COMPBESSED AIE OUST THE MEK 

These were not so serious as first anticipated. The 
few cases of death that occurred could in but two 
instances be charged to the effects of the pressure. 

As the latter increased, the working hours below 
were gradually reduced from four hours to two hours, 
twice a day, at 35 pounds. It is true that scarcely any 
man escaped without being somewhat affected by 
intense pain in his limbs or hones or by a temporary 
paralysis of arms and legs, hut they all got over it, either 
by suffering for a few days outside, or by applying the 
heroic mode of returning into the Caisson at once, as 
soon as the pains manifested themselves. 

The shortening of the hours of labor produced the 
best results in keeping the men in good condition, but 
even this was not necessary for all constitutions, be- 


28 


cause some could remain below with impunity for six 
hours at the highest pressure. 

After the locks were passed the men had their choice 
of coming up either by an elevator or by circular 
stairs. 

During the winter months all tendency to congestion 
of the lungs, owing to the sudden change of tempera¬ 
ture in coming out of the locks, was controlled by 
means of steam coils in the latter, so arranged as to 
warm the air when coming out of the lock and to cool 
it when passing in. 

The general condition of the air below was very 
pure, due to the absence of candles, and illumination by 
gas alone. 

Mr. Collingwood found that as the pressure in¬ 
creased the gas-burners gave more light, and at 35 
pounds a 1-foot burner gave as much light as a 
4-foot burner outside. We therefore had a maxi¬ 
mum production of light with a minimum production 
of irrespirable gases. 

The services of Dr. A. H. Smith were engaged for 
the purpose of attending to all Caisson cases and ex¬ 
amining new candidates for work below. He has been 
quite successful in his treatment, and it is to be hoped 
that his experience will be made public for the benefit 
of future works. 

The fact remains, however, that the effects of com¬ 
pressed air on the human system constitute the principal 
difficulty attending deep pneumatic foundations. Men 
are somewhat difficult to get, wages are high, and the 
time of labor becomes so short that the work must 
necessarily be done under a disadvantage and under an 
immense amount of supervision, where it is at all diffi¬ 
cult or different from ordinary digging in a uniform 
material. 


29 


Besides two general foremen and fifteen under 
bosses, it required the daily attendance of botli Col. 
Paine and Mr. Collingwood, assisted occasionally by 
Mr. Martin and Mr. McNulty, to keep matters moving 
smoothly below and in conjunction with affairs above. 

An ingenious mechanical telegraph, contrived by Col. 
Paine, proved of great assistance in keeping up com¬ 
munication between the upper and lower world. 

LIGHTING THE CAISSON. 

The ordinary street gas has been the only agent used 
for illumination. Sixty burners, divided among the six 
chambers, gave all the light required. The gas was 
burned under a pressure of one or two pounds in 
excess of the Caisson pressure, and was at all times 
uniform and plentiful in supply. 

In order to maintain a uniform overpressure of the 
gas below, independent of t|e sinking of the Caisson, 
a strong cylindrical tank, 6 feet long and 3 feet 
in diameter, was placed in the air chamber. This com¬ 
municated by means of a water-pipe with another tank 
of the same size on the dock, several feet above the 
water level. A column of water was thus established 
having a head always a few pounds in excess of the 
Caisson pressure, and capable of forcing the gas out of 
the lower tank into the air chamber. 

A gas pump above forced the gas steadily into the 
tank below, and as the latter would fill with gas it 
raised the column of water in the tank above, where, 
at a certain stage, a float controlled the throttle-valve 
of the gas pump, and thus regulated the supply of gas 
within restricted limits, the whole arrangement being- 
self-acting. 

One interesting fact was observed which may possi¬ 
bly be new, and that is, that in compressed air all gas- 




30 


lights become sensitive flames, answering to the stroke 
of a hammer on a piece of iron, or even to tones of 
the voice. 

MOVEMENTS OE THE CAISSON. 

The downward movement of the Catsson has been 
under perfect control throughout the whole of the sink¬ 
ing. It usually occurred at low tide and was very 
gradual, owing principally to the wide frames and broad 
shoe. 

While the Caisson was passing through the mud, 
river sand, and gravel, the frames sank through the 
material without digging, but in the quicksand and 
harder material below, the whole frames had to be dug 
out underneath before settlement would take place. 

The Caisson also sank perpendicularly in its true 
place, no movement occurring in any direction. This 
result was principally owing to the facility with which 
- it was kept level by digging. 

The side friction was considerable, but difficult to 
estimate, because the frames and shoe were seldom 
entirely clear. It could not have been less than 600 
pounds per square foot of external surface, vary¬ 
ing with the amount of air passing out under the 
shoe. 

The total resistance offered by the side friction is, 
however, quite small when compared with the total 
bulk. At a depth of 78 feet the side friction amounted 
to 6,000 tons, whereas the weight of the whole founda¬ 
tion, including masonry, was 53,000 tons. 

At 78 feet the excess of the downward pressure of 
the Caisson over the upward pressure of the air at low 
tide would average from 10 to 12,000 tons, not including 
side friction. The air pressure has, however, frequently 
run so low as to give an excess of downward pressure 


31 


of 15,000 tons. An excess of overweight is in all 
cases an advantage, as it saves considerable dig¬ 
ging. 

The experience with this foundation goes to show 
that a larger Caisson is much easier to handle, is safer 
and under more perfect control than a smaller one. 
The labor question, however, becomes the most serious 
drawback where a considerable number of men have to 
be brought together under abnormal circumstances. 
The forces of nature may be measured and brought 
under control, provided they are properly understood, 
but human nature is not so amenable to laws. 

THE BROOKLYN TOWER. 

The work of laying masonry on this Tower has pro¬ 
gressed steadily. Seventy-five feet in height have been 
laid since June 1, 1871, amounting to 9,300 yards of 
masonry. Twenty feet more are required to bring it 
up to the level of the roadway. 

Below the roadway a number of heavy steel and 
iron bars will be set in the masonry for a variety of 
purposes. They comprise six sets of cast-steel bars, 10 
by 2 inches, and 60 feet long, passing around the out¬ 
side of the Tower, between the masonry courses, and 
serving as an attachment for the main under-floor 
storm cables. 

In addition, there are sixteen sets of cast-steel bars 
passing through the connecting walls and into the main 
buttresses. To these will be attached the six lines 
of trusses of the Bridge as well as sixteen counter¬ 
stays to the cables. 

The iron bars comprise four smaller sets for under¬ 
floor stays and twenty sets of long tie bars to be laid in 
the connecting walls below the floor. They are all 
„ galvanized as a protection against rust. The steel bars 


32 


were made by the Butcher Works, of Philadelphia; 
the others at Phcenixville. 

All the stone required to complete the masonry to 
the roadway are on hand, and at no time has there 
been any interruption in the work for want of stone. 

The laying of stone was continued during a portion 
of the cold weather in December last, with a view of 
bringing the masonry to a certain stage where the 
winter months could be utilized in removing the old 
boom derricks and putting up a new set of hoisting 
machinery. 

By a plentiful use of hot water and salt, this portion 
of the wall has been laid equally as well as the rest, 
especially as that proportion of the wall occupied by the 
cement and concrete amount to only one-tenth of the 
whole bulk. 

NEW DEKBICKS. 

The difficulty of guying ordinary boom derricks at the 
water edge at an elevation of 80 feet, becomes so great, 
that another arrangement of stone-hoisting and stone¬ 
setting machinery was accordingly prepared during the 
summer of 1871, and put in position during last winter. 
These new derricks will lay all the masonry to the top 
of the Tower. 

The arrangement in general consists of three balance 
derricks, one in the center of each shaft. Each derrick 
stands on a turn-table, 6 feet in diameter, provided with 
conical rollers, and having a safety tail extending 
through the turn-table into the well-hole below. 

The weight of the stone is balanced by a weight of 
pig iron, run in or out on the opposite boom as occa¬ 
sion may require. The setting of the stone is done by 
two small steam engines attached to the mast of each 
derrick, steam being led up to the Tower from a boiler 


33 


in the yard below. The derricks are raised course by 
course by means of hydraulic jacks. 

Their chief merit consists in their absolute safety, 
there being no possibility of one falling over. With the 
boom derricks, however, ffhere are numerous guys with 
hundreds of connections, any one of which giving way 
may involve the downfall of the whole system. 

Such an occurrence took place last October, when by 
the giving way of a defective weld, two derricks fell, 
resulting in the death of three men and wounding of 
five others. 

In connection with the setting derricks is a double 
system of stone hoists, consisting of two railroad tracks, 
always at a level with the top of the wall, and two 
hoisting frames. The stone are raised at a single lift by 
an endless rope, operated by an engine and powerful 
machinery in the yard below. 

Stone weighing seven tons are raised at the rate of 
100 feet per minute, and are supplied as rapidly as the 
setting derricks can dispose of them. These tracks are 
raised every 4 feet. 

The general arrangement is essentially the same as 
that used in building the towers of the Cincinnati Sus¬ 
pension Bridge. 


THE ANCHORAGES. 

Both Towers being fairly under way, I would recom¬ 
mend the early acquisition of the ground required for at # 
least one anchorage, so as to make a beginning this 
season, and utilize the coming winter by putting in the 
foundation. 

The quantity of masonry in one anchorage is about 
the same as in a Tower, although of a less costly char¬ 
acter and more easily put in place. 

Both the Towers and the anchorages have to be 


34 


completed before any thing can be done with the neces¬ 
sary preparations for cable-making. 

• CONCLUDING REMARKS. 

The pleasant task remains yet of expressing my 
thanks to the gentlemen who have so ably assisted in 
the prosecution of the work, and to whose untiring 
industry, constant watchfulness, and sound judgment, 
is mainly due the success which has attended it to the 
present time. 

The work in the Caisson has been carried on under 
the daily supervision of both Col. Paine and Mr. Colling- 
wood, relieved at times by Mr. Martin and Mr. McNulty, 
whenever the outside duties of these latter gentlemen 
would permit. 

The labor below is always attended with a certain 
amount of risk to life and health, and those who face 
it daily are therefore deserving of more than ordinary 
credit. 

The general foremen below have been Messrs. 
Green, Young, Woliver, OMalley, and Korner, assisted 
by twelve under foremen. 

The masonry, carpentry, and machine departments 
have, as usual, been most efficiently attended to by 
Messrs. Douglass, Farrington, and Smith; while the 
draughting-room has been in charge of Mr. Hilden- 
brandt, and occasionally Mr. Yonder Bosch. 

• To Mr. Horatio Allen, consulting engineer, my 

acknowledgments are due for his continued counsel and 
advice. 

In regard to the relations of the engineering depart¬ 
ment and the general management, it gives me pleasure 
to bear testimony that all requisitions from the engineer 
department have been met with the utmost promptness, 
both in respect to quantity as well as quality, and that 


35 


the relations of the different executive branches have 
been conducted with a mutual co-operation, conducive 
to the highest results, both in efficiency and economy. 

Respectfully submitted, 

W. A. ROEBLINGf, 

Chief Engineer N. Y. Bridge Co. 


* 























REPORT 


OF THE 

GENERAL SUPERINTENDENT, 

BROOKLYN, JUNE 1, 1872. 


Hon. Henry 0. Murphy, President New York 

Bridge Company: 

Dear Sir:— 

During the last year satisfactory progress has been 
made in the construction of the Towers for the East 
Eiver Bridge, no serious or unexpected delay haying- 
occurred in any part of the work. 

BROOKLYN TOWER. 

Since the date of my last report about 14,500 cubic 
yards of masonry have been laid on the Brooklyn 
Tower, and it is now about 100 feet above high water. 
All of the machinery designed for hoisting and setting 
stone has answered its purpose remarkably well, so that 
although the Tower is now nearly 100 feet high, yet no 
difficulty is experienced in getting stone to the top of 
it as fast as it can be laid by the masons. 



38 


On the 23d of October, owing to a defective weld in 
a rope socket, two of the derricks fell, causing the 
death of three men and the wounding of several others. 
A thorough investigation was asked for and was made 
by the Coroner, which resulted in a verdict entirely 
exonerating the Bridge Company from all blame. The 
investigation also made public the fact, that only the 
best quality of material and workmanship were used 
by the Bridge Company in the construction of all the 
appliances for handling stone, and that every precau¬ 
tion was taken to guard against accidents. This has 
been the case from the first and will continue to be; 
no labor or expense will be spared to insure the safety 
of the employees. The setting of stone was suspended 
in February on account of the frost, and during the 
balance of the winter the boom derricks were removed 
and the balance derricks erected. These will be used 
until the Tower is completed. The mason-work was 
resumed on the 10th of April, and has proceeded regu¬ 
larly and satisfactorily since. 

NEW YOEK TOWER. 

At Pier 29 possession of the Williamsburgh Ferry 
slip was not obtained until April 4, 1871, when work 
was at once commenced. This consisted principally in 
removing the ferry racks and building a pile dock or 
platform upon which to erect buildings for the machin¬ 
ery and workshops and for storing materials; also pre¬ 
paring an inclosure of piling to receive the Caisson. 
This new dock covered an area of about 32,000 square 
feet, and was so far completed by September 9 as to be 
ready for the Caisson. As soon as the Caisson was in 
place the inclosure was completed around it, and the 
up and down stream outer corners were made extra 
strong to resist the action of floating ice during the 


39 


winter. This was a wise precaution, as several heavy 
fields of ice struck the pier, yet no serious damage was 
done. The first stone of the New York Tower was 
laid October 31. The stone setting progressed 
slowly until November 17, when the regular derricks 
were in position, and from that time it proceeded as 
rapidly, as was necessary for the proper sinking of the 
Caisson, the masonry at all times being kept above 
high water. 13,075 cubic yards of masonry have been 
laid on the New York Tower. 

NEW YORK CAISSON. 

The Caisson for the New York Tower remained at 
the Atlantic Dock until seven additional courses of 
timber were placed upon it. This was accomplished 
early in September, and on the 9th of that month the 
Caisson was towed to Pier 29 and placed in position in 
two and a half hours, under the piloting of Cap¬ 
tain Murphy, the well known Sandy Hook pilot. The 
work of putting on ten additional courses was at once 
proceeded with, and completed October 31, when the 
masonry was commenced. Sufficient masonry was laid 
by December 12 t#hold the Caisson on the ground at 
high tide, when it was filled with air and a gang of 
thirty-six men were at once set at work inside of it. 
This force was gradually increased until about one 
hundred and fifty men were employed in the Caisson. 
After getting through the dock mud, timber, and loose 
stone of Pier 29, below the dredging, the material was, for 
some distance, mostly sand and gravel, which rendered 
the excavation much easier than that for the Brooklyn 
Tower. The result was that for several weeks the 
Caisson was sunk on an average of 6 inches per day,' 
and when it is remembered that it covers an area of 
17,544 square feet, the rapidity of the work will be 


40 


appreciated. Toward the last the material varied 
much in its character: sand, quicksand, gravel, boul¬ 
ders, and clay being met with. This required varied 
appliances and devices for its rapid and economical 
excavation, for an account of which you are referred 
to the report of the Chief Engineer. 

The sinking of the Caisson was successfully accom¬ 
plished on May 18, the lower edge being 78 feet below 
high water, and resting upon a foundation that is 
entirely satisfactory, rock having been reached. 

The work of excavating in the Caisson was com¬ 
menced December 12 and completed May 18, being a 
few days over five months, during which time about 
26,000 cubic yards of excavation had been made in 
compressed air, varying from a pressure of about 
17 pounds per square inch at the first to 36 pounds 
at the last, and at depths varying from 37 feet at the 
first to 78 feet at the last, below high water. The 
work of filling the Caisson with concrete was com¬ 
menced as soon as the sinking was completed, and is 
progressing as rapidly as is considered expedient, and 
will probably be completed by July 1, when the lay¬ 
ing of masonry will be recommenced and pushed 
vigorously during the season. 

Knowing from the reports of other similar works that 
compressed air was liable to affect some men unfavor¬ 
ably, every known precaution was taken to guard 
against this danger. When the pressure had reached 
25 pounds per square inch, Dr. Andrew H. Smith, 
a competent physician, was employed to visit the 
work once each day, and to look after the health 
of the men. He carefully and thoroughly examined 
every man who was at work in the Caisson, and, from 
that time to the present, every new man employed to 
work in the Caisson has been subjected to a physical 


41 


examination by a physician, and all who were found 
untit for such work, for any cause, were at once reject¬ 
ed. It being well established, that, upon coining out 
of compressed air, rest is essential to health, a commo¬ 
dious and well-ventilated room was set apart for the 
exclusive use of the Caisson men, and fitted up with 
bunks, blankets, and pillows, so that they could lie down 
and rest while off duty. By the advice of the physician, 
good hot coffee was prepared for the men every time 
they came out of the Caisson. Notwithstanding all of 
the precautions taken, three of the workmen have died 
from the effects of the compressed air, but the number 
has been much less in proportion to the number of 
men employed than upon any similar work of which 
we have any account. A full report will be made by 
Dr. Smith, embracing all of the facts and conclusions 
derived from a very close and careful study of the 
effects of compressed air. This report will be especially 
valuable, as the process of constructing foundations by 
the aid of compressed air is destined to become very 
common, and, this being the largest work of the kind 
ever executed , or likely to be, the information gained 
here is varied and valuable. 

* 

LABOK. 

Notwithstanding the peculiar and unusual character 
of the Caisson work, and the fact that it is not without 
danger to health and even life, no difficulty has been 
experienced in obtaining all of the labor required, and 
at moderate wages. The price paid at first was 25 
cents per hour, or $2 for a day’s work of 8 hours. 
At the last the price was 69 cents per hour, or $2.76 
for a day’s work of 4 hours. The time of working 
in the Caisson was regulated by the advice of Dr. 
Smith, and was successively reduced from 8 to 71, 7, 6, 


42 


and 5 and 4 hours per day, as the pressure increased. 
But one strike occurred. This was by the Caisson men, 
and continued but four days, when the men resumed 
work upon the terms offered by the Bridge Company. 

PURCHASES. 

The purchasing of supplies for the work has been 
under the charge of the Treasurer of the Company, 
Mr. John H. Prentice, and constant vigilance has been 
exercised to obtain all goods at the lowest possible 
rates, and in almost all cases the full trade discounts 
have been obtained. 


CONTRACTS. 

The principal contracts entered into during the year 


were as follows: 

1871. Divine Burtis. 

.June5.—Putting 7 courses of timber on Caisson, each.. .$1,400 00 
“ 10 “ “ “ “ . .. 1,125 00 

Building coffer-dam. 2,000 00 

Hubbard & Whitaker. 

il 12.—8 sets double hoisting engines, each.. 2,250 00 

Wm. Butcher & Co. 

Steel anchor bars, per lb. 11 

John Roach & Son. 

• Air locks, per lb..... 11 

New York & Brooklyn Saw Mill Co. 

July 10.—White pine sheet piling, 6 inches by 50 feet, per 

M, board measure. 37 00 

Read & Morrell. 

2,000 cubic yards limestone, per cubic yard. .*.. 14 00 

Lake Champlain Blue-Stone Co.] 

Sept. 7.—2,000 cubic yards limestone, per cubic yard.... 13 95 







43 


Phelps & Kimpland. 

Sept. 7.—10,000 lineal feet white pine dock timber, per M, 


board measure. $22 50 

Hubbaed & Whitakee. 

4 tubular boilers. 2,680 00 

Phelps & Kimpland. 

500 spruce piles, 55 to 70 feet, 14 to 16 inches, 

each. .. 6 00 

500 spruce piles, 40 to 55 feet, 14 to 16 inches, 

each. 5 75 

100 oak piles, 60 feet, 16 to 20 inches, each.... 20 00 

75 “ “ 50 feet, 16 to 18 inches, each.. . .16 00 

John Roach & Son. 

Oct. 9.—8 sections supply shaft, per lb. 12 

A. Ammeeman. 

150,000 feet board measure, white pine, 6 inches 

thick, special lengths and widths, per M... 40 00 

Noone & Co. 

Nov. 6.—2,500 cubic ya'rds limestone, per cubic yard_ 14 00 

Moeton & Canda. 

3,500 bbls. cement, each. 1 75 

A. S. Cameeon & Co. 

Nov. 13.—1 Cameron pump.. 1,300 00 

John Roach & Son. 

14 sections of water shaft, per lb. Ilf 

1872. W. H. Dunn. 

Jan. 6.-20,000 lineal feet, 10 by 10 inch, spruce, per 

M, board measure.*. 25 00 


ENGINEERING AND SUPERINTENDENCE. 

Every step in the progress of the work has been 
taken by the direction and under the superintendence 
of Ool. Koebling or his assistants, and the rapid 
progress of the work and the successful accomplishment 











44 


of one of the most difficult engineering undertakings of 
the age, is evidence of the care, ability, and skill which 
have been bestowed upon it. 

The masonry has been under the charge of Thomas 
G. Douglas, as general foreman, assisted by Thomas 
Malloy and Robert Ast. This work has progressed 
rapidly, over 27,000 cubic yards of masonry having 
been laid during the year. 

The work in the Caisson was, at first, under the 
charge of General Foreman C. W. Young, and as the 
work progressed and a second gang of men were set at* 
work, Mr. Cornelius Creen was employed as general 
foreman of this gang, and has performed the duties 
of the position very satisfactorily. After working in the 
Caisson about three months, Mr. Young was so much 
affected by the compressed air and long-continued* 
work in the Caisson, that by advice of his physician he 
resigned his position. He has since been employed in 
charge of work on the dock. He* has probably had 
more experience in continuous work in compressed air 
than any other man living. 

His place was filled by Mr. O’Malley, now in charge 
of the gang, who has proved himself a thorough and 
efficient general foreman. 

Mr. E. F. Farrington is still master carpenter, and 
has performed all of his duties promptly and efficiently. 

Mr. A. H. Smith is still in charge of all of the 
machinery, and has attended faithfully to his duties. 

Mr. F. Mallard, in charge of the stone-yard, has 
handled the thousands of yards of stone received and 
shipped from that point during the year, without acci¬ 
dent, and at a very low rate of cost. 

The Yew York Bridge Company have every reason 
to be gratified with the past progress of the work, and 
to be hopeful as to its ultimate success. The Brooklyn 


45 


Tower is now nearly 100 feet above high water, over 
20,000 cubic yards of masonry having been laid, and 
every thing is in perfect order, and the work progressing 
as rapidly as possible. The New York Caisson is sunk 
to its final resting-place, and the work of filling it with 
concrete Js going on rapidly. Over 13,000 cubic yards 
have been laid on that tower, and it is now above high 
water. Every thing is in readiness for laying masonry 
again as soon as the Caisson is filled. 

Very respectfully, 

W. C. KINGSLEY, 

General Superintendent. 






























